diff options
| -rw-r--r-- | tests/rcutorture.c | 55 |
1 files changed, 37 insertions, 18 deletions
diff --git a/tests/rcutorture.c b/tests/rcutorture.c index 256d24ed5b..732f03abda 100644 --- a/tests/rcutorture.c +++ b/tests/rcutorture.c @@ -230,13 +230,12 @@ static void uperftest(int nupdaters, int duration) #define RCU_STRESS_PIPE_LEN 10 struct rcu_stress { - int pipe_count; + int age; /* how many update cycles while not rcu_stress_current */ int mbtest; }; struct rcu_stress rcu_stress_array[RCU_STRESS_PIPE_LEN] = { { 0 } }; struct rcu_stress *rcu_stress_current; -int rcu_stress_idx; int n_mberror; /* Updates protected by counts_mutex */ @@ -261,7 +260,7 @@ static void *rcu_read_stress_test(void *arg) while (goflag == GOFLAG_RUN) { rcu_read_lock(); p = atomic_rcu_read(&rcu_stress_current); - if (p->mbtest == 0) { + if (atomic_read(&p->mbtest) == 0) { n_mberror++; } rcu_read_lock(); @@ -269,7 +268,7 @@ static void *rcu_read_stress_test(void *arg) garbage++; } rcu_read_unlock(); - pc = p->pipe_count; + pc = atomic_read(&p->age); rcu_read_unlock(); if ((pc > RCU_STRESS_PIPE_LEN) || (pc < 0)) { pc = RCU_STRESS_PIPE_LEN; @@ -288,32 +287,52 @@ static void *rcu_read_stress_test(void *arg) return NULL; } +/* + * Stress Test Updater + * + * The updater cycles around updating rcu_stress_current to point at + * one of the rcu_stress_array_entries and resets it's age. It + * then increments the age of all the other entries. The age + * will be read under an rcu_read_lock() and distribution of values + * calculated. The final result gives an indication of how many + * previously current rcu_stress entries are in flight until the RCU + * cycle complete. + */ static void *rcu_update_stress_test(void *arg) { - int i; - struct rcu_stress *p; + int i, rcu_stress_idx = 0; + struct rcu_stress *cp = atomic_read(&rcu_stress_current); rcu_register_thread(); - *(struct rcu_reader_data **)arg = &rcu_reader; + while (goflag == GOFLAG_INIT) { g_usleep(1000); } + while (goflag == GOFLAG_RUN) { - i = rcu_stress_idx + 1; - if (i >= RCU_STRESS_PIPE_LEN) { - i = 0; + struct rcu_stress *p; + rcu_stress_idx++; + if (rcu_stress_idx >= RCU_STRESS_PIPE_LEN) { + rcu_stress_idx = 0; } - p = &rcu_stress_array[i]; - p->mbtest = 0; + p = &rcu_stress_array[rcu_stress_idx]; + /* catching up with ourselves would be a bug */ + assert(p != cp); + atomic_set(&p->mbtest, 0); smp_mb(); - p->pipe_count = 0; - p->mbtest = 1; + atomic_set(&p->age, 0); + atomic_set(&p->mbtest, 1); atomic_rcu_set(&rcu_stress_current, p); - rcu_stress_idx = i; + cp = p; + /* + * New RCU structure is now live, update pipe counts on old + * ones. + */ for (i = 0; i < RCU_STRESS_PIPE_LEN; i++) { if (i != rcu_stress_idx) { - rcu_stress_array[i].pipe_count++; + atomic_set(&rcu_stress_array[i].age, + rcu_stress_array[i].age + 1); } } synchronize_rcu(); @@ -346,7 +365,7 @@ static void stresstest(int nreaders, int duration) int i; rcu_stress_current = &rcu_stress_array[0]; - rcu_stress_current->pipe_count = 0; + rcu_stress_current->age = 0; rcu_stress_current->mbtest = 1; for (i = 0; i < nreaders; i++) { create_thread(rcu_read_stress_test); @@ -376,7 +395,7 @@ static void gtest_stress(int nreaders, int duration) int i; rcu_stress_current = &rcu_stress_array[0]; - rcu_stress_current->pipe_count = 0; + rcu_stress_current->age = 0; rcu_stress_current->mbtest = 1; for (i = 0; i < nreaders; i++) { create_thread(rcu_read_stress_test); |